FIG. 1 shows a conventional single-phase brushless motor 10, which comprises a stator 11 and a rotor 19 installed in the stator 11. The stator 11 comprises a stator core 12 and a winding 13 wound on the stator core 12. The stator core 12 comprises an annular yoke 14 and a plurality of teeth 15 extending inwardly from the yoke 14. Slots 16 are formed between adjacent teeth 15 for receiving coils 13A of the winding 13. The yoke 14 and the teeth 15 of the stator core 12 are integrally formed into a single integral structure. Each tooth 15 forms a stator pole 15A, which comprises a pole shoe 18 formed at the end of the tooth 15. The pole shoe 18 extends along the circumferential direction of the motor 10. A slot opening 17 is formed between adjacent pole shoes 18 to allow access for winding the respective coils 13A about each of the teeth 15. Therefore, a non-uniform air gap 17A is formed between the stator 11 and the rotor 19.
In the above conventional single-phase brushless motor 10, however, the presence of the slot openings 17 can make the motor 10 generate an unduly large cogging torque. The cogging torque can result in the motor 10 generating vibration and noise during use. Furthermore, since the stator core 12 of the motor 10 is provided as an integral structure, a reciprocating shuttle winding machine is required for winding the coils 13A. But, use of the reciprocating shuttle winding machine causes a low winding efficiency.
In view of the foregoing, there is a need for a motor that can operate with low vibration and noise and that can be manufactured in a more efficient manner, overcoming disadvantages of existing motors.